CHANGE OF THE SUN'S DECLINATION, &C 29 



rous as the stars, flew in all possible directions, except from the 

 earth, toward which they all inclined more or less ; and some 

 of them descended perpendicularly over the vessel we were in, 

 so that I was in constant expectation of their falling among us. 

 My thermometer which had been at 86° of Farenheits scale 

 for four days, fell to 56° about -i- o'clock. A. M. and nearly at 

 the same time the wind shifted from the South to the N. W. 

 from whence it blew with great violence for three days without 

 intermission. We were in latitude 25 ° N. and S. E. from Kay 

 Largo, near the edge of the Gulph Stream." 



I have since been informed that the above phenomenon ex- 

 tended over a large portion of the West India islands and as 

 far North as Mary's in latitude 30° 42' where it appeared as bril- 

 liant as with us off Cape Florida. 



No. VI. 



Improved method of projecting and ineasuring plane Angles by Mr* 

 Robert Patterson communicated by Mr. Andrew Ellicott. 



Read 6th March, 1801. 

 SIR, 



THE laying down, and measuring of plane angles, con- 

 stitute so great a part of practical geometry, that any attempt 

 to render this operation more easy and acurate than by the line 

 of chords, or any other method now in common use, will not, 

 I presume, be deemed altogether unimportant. 



The lines of chords on our common scales are in general 

 very inaccurately divided, and even if we suppose the divisions 

 ever so exact it will still be impracticable to take off the mea- 

 sure of an angle to greater accuracy then a half or third of a 

 degree at most ; as it is impossible to apply either the nonius or 

 diagonal method of subdivision to a line of unequal parts. 



But in the method that I am about to propose a line of equal 

 parts only is used, and therefore the divisions and subdivisions 

 may, by either of the above modes, be made as minute and ac- 

 curate as can be desired. 



